[Qgis-user] problème lors de l'export d'un nuage de points (LIDAR HD) en MNT

[Pascal WISSENBERG]

Hi Andrea,
With your latest advice, everything is working again: I did indeed 
forget to repeat "Classification="
Thank you very much.
Best regards.

PW

Le 14/12/2025 à 21:04, Andrea Giudiceandrea a écrit :
> Hi Pascal,
> in my previous message I advised you to install QGIS LTR 3.40.7, not 
> QGIS LTR 3.40.4.
>
> Anyway, QGIS LTR 3.40.4 should also work (since the original error 
> doesn't occur, according to the log), provided that your system has 
> enough free resources to perform the task and that the algorithm's 
> parameters value are correct.
>
> It looks like this time the pdal_wrench application (which the 
> processing algorithm relies on) crashed because you have set the 
> FILTER_EXPRESSION parameter with an incorrect expression (previously 
> you have set a different and correct expression, instead).
>
> The expression "Classification = 2 OR 6" is incorrect.
>
> An equivalent correct one is "Classification = 2 OR Classification = 6".
>
> Moreover, are you sure your system has enough free RAM and storage 
> space to process a copc file containing 32 millions points on a 1000m 
> x 1000m area in order to create a 20'000px x 20'000px raster GeoTIFF 
> (due to the fact that you have set RESOLUTION=0.05)?
>
> Regards.
>
> Andrea
>
> Il 14/12/2025 15:21, Pascal WISSENBERG ha scritto:
>> I installed version 3.40.4 ltr and when I use the same "export to 
>> raster" algorithm, I get a new message:
>
>> { 'FILTER_EXPRESSION' : 'Classification = 2 OR 6', 'FILTER_EXTENT' : 
>> None, 'INPUT' : 'copc://E:/My Documents/QGIS/LIDAR 
>> tiles/LHD_FXX_0801_6398_PTS_LAMB93_IGN69.copc.laz', 'ORIGIN_X' : 
>> None, 'ORIGIN_Y' : None, 'OUTPUT' : 'E:/My Documents /QGIS/dalles 
>> MNT/0801-6398k.tif', 'RESOLUTION': 0.05, 'TILE_SIZE': 1000 }
>
>> The process stopped so unexpected